Use of Saline Groundwater and Produced Water for Makeup of Hydraulic Fracturing Fluids

During the high volume hydraulic fracturing (HVHF) of low-permeability oil and gas formations such as shales, water quantities for fracturing range from about 3 to 6 million gallons per well. To date, much of this water has come from fresh water sources such as rivers, lakes, and drinking water aquifers, which can be a conflict with local uses, such as drinking water.  While the water volumes used for HVHF are small compared with other users such as municipalities, agriculture, and electricity generators, many operators are pursuing strategies to reduce their fresh water demands.  With much of the country in drought conditions and traditional fresh water sources becoming increasingly unavailable for oil and gas operations, interest in such strategies is increasing.

A key element to sustainable development of critical oil and gas resources is consideration of alternative water sources, particularly saline groundwater and recycled produced water from fracturing.  Now, with effective formulations being developed for higher salinity fracturing fluids, use of the more saline source waters can reduce and even eliminate conflicts for fresh water resources.  Higher salinity fracturing fluids are becoming more typical with both economic and environmental advantages.  However, in order to ensure that the fracturing fluid is effective, the mixing of fresh water with these more saline waters must be carefully planned in order to understand the chemical reactions that will occur, and treatment is typically required.

This article presents an overview of the factors that affect the use of saline groundwater and produced water to supplement or replace fresh water used for HVHF, including considerations for mixing and water treatment.